Home >

news Help

Publication Information


Title
Japanese:Magnetic susceptibilities in a family of S=1/2 kagome antiferromagnets 
English:Magnetic susceptibilities in a family of S=1/2 kagome antiferromagnets 
Author
Japanese: 小野 俊雄, 森田 克洋, 矢野 みどり, 田中 秀数, 藤井 孝太郎, 植草 秀裕, 鳴海 康雄, 金道 浩一.  
English: T. Ono, K. Morita, M. Yano, H. Tanaka, K. Fujii, H. Uekusa, Y. Narumi, Koichi Kindo.  
Language English 
Journal/Book name
Japanese:Physical Review B 
English:Physical Review B 
Volume, Number, Page Vol. 79    No. 17    174407
Published date July 2009 
Publisher
Japanese: 
English:American Physical Society 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
English: 
Official URL http://link.aps.org/doi/10.1103/PhysRevB.79.174407
 
DOI https://doi.org/10.1103/PhysRevB.79.174407
Abstract Hexagonal antiferromagnets Cs2Cu3MF12 (M=Zr, Hf, and Sn) have uniform kagome lattices of Cu^2+ with S=1/2, whereas Rb2Cu3SnF12 has a 2a×2a enlarged cell as compared to the uniform kagome lattice. The crystal data of Cs2Cu3SnF12 synthesized in the present work are reported. We performed magnetic-susceptibility measurements on this family of kagome antiferromagnet using single crystals. In the Cs2Cu3MF12 systems, structural phase transitions were observed at Tt=225, 172, and 185 K for M=Zr, Hf, and Sn, respectively. The magnetic susceptibilities observed for T>Tt are almost perfectly described using theoretical results obtained by exact diagonalization for the 24-site kagome cluster with J/kB=244, 266, and 240 K, respectively. Magnetic ordering accompanied by the weak ferromagnetic moment occurs at TN=23.5, 24.5, and 20.0 K, respectively. The origins of the weak ferromagnetic moment should be ascribed to the lattice distortion that breaks the hexagonal symmetry of the exchange network for T<Tt and the Dzyaloshinsky-Moriya interaction. Rb2Cu3SnF12 is magnetically described as a modified kagome antiferromagnet with four types of neighboring exchange interactions. Neither structural nor magnetic phase transition was observed in Rb2Cu3SnF12. Its magnetic ground state was found to be a spin singlet with a triplet gap. Using exact diagonalization for a 12-site kagome cluster, we analyzed the magnetic susceptibility and evaluated individual exchange interactions. The causes leading to the different ground states in Cs2Cu3SnF12 and Rb2Cu3SnF12 are discussed.

©2007 Tokyo Institute of Technology All rights reserved.